Field of the Invention
The present invention generally relates to wired and wireless communication networks and more particularly to establishing a mesh network with wired and wireless links.
Description of Related Art
A mesh network allows for communication of information through multiple nodes, which may be distributed over a wide area. The multiple nodes allow for an information packet to travel through multiple routes to a given receiving node or device. The nodes in a mesh network may communicate through wired (e.g. Ethernet) or wireless connections (e.g., IEEE 802.x).
In a lightweight mesh network, a single wired node may serve as an access point (e.g., a base station). The base station may be in communication with multiple wireless receiving nodes. Each node may have an internal mesh basic service set (MBSS). Each MBSS in the mesh network may have a unique basic service set identifier (BSSID) but share an identical service set identifier (SSID) and/or pre-shared key (PSK). A node may identify another node in the network by reference to that node's BSSID. The transmission of an information packet from one node to another may be referred to as a hop. Each of the nodes in a mesh network may connect with one another through one or more hops. For example, a first receiving node, or child node, receives information from a parent node via one hop.
A mesh network where all nodes are directly connected to one other may be referred to as a fully connected network. A mesh network where only some nodes are connected to all other or a subset of nodes may be referred to as a partially connected network. Information transmission in a fully connected network may take only one hop (e.g., from a originating node to a destination child node). In a partially connected mesh network, however, information transmission may require multiple hops through multiple nodes. If there is one node is not directly connected to a particular destination node, transmission of information from the origin to the destination may require passage through an intermediate node (or nodes) thereby invoking at least a two hop transmission.
In a network composed of wireless and wired links, an information packet may be transmitted to a receiving node or device through multiple nodes over wireless and/or wired connections. Where two nodes are connected by a wireless and a wired link (e.g., an 802.x and an Ethernet connection), the wired link may serve as an alternate route by which the information packet may travel; the wireless connection may be the primary means of packet delivery. The particular route taken by an information packet may be determined by various available routing algorithms at the originating and/or intermediate nodes. Routing algorithms generally seek to transmit and allow for the delivery of information packets to a destination node as quickly and efficiently as possible.
Determining a route in a partially connected network or wired and wireless connections presents a difficult optimization problem. Routing algorithms may have to determine how a node learns what other nodes are available, with which of the other node(s) to associate, which associations allow for the quickest and most efficient information transfer, and the reliability of those connections. Some routing algorithms may determine or require that a receiving node be associated with particular route(s) and/or particular parent node(s).
Various circumstances may nevertheless require that a route be changed for a given receiving node. For example, an intermediate transmission node may fail whereby the receiving node and/or parent node has to associate with a different intermediate node. Other circumstances requiring a change in routing may include changes in network traffic volume, changes in data rates, security requirements, and even changes in environmental conditions that might affect the network (e.g., the weather).
Another problem experienced by a mesh network is loop formation. A loop can form where two nodes are connected by both a wired and wireless link. Since an information packet can travel through any of the two links between the two nodes, it is possible that once a packet is transmitted to a receiving node via the wired link, the packet can be transmitted back to the sending node via the wireless link or vice versa. A loop may be formed resulting in data transmission that continually repeats between two nodes. The result is delays in data transmission and decreased network capacity.